Kern IRWMP Participants Group c/o Ms. Lauren Bauer, Water Resources Planner

Transcription

1 To: From: Subject: Mary Lou Cotton Vulnerability to Climate Change K/J Climate change refers to significant changes in temperature, precipitation, wind patterns and other weather that occur over several decades and beyond. Climatic changes observed in recent decades are occurring due to rising average global temperatures that are the result of elevated levels of gases released primarily by human activities, which trap heat in the atmosphere in a process known as the greenhouse effect. These so-called greenhouse gases (GHGs) include, among others, water vapor, carbon dioxide (CO 2 ) and methane (CH 4 ). Climate change is impacting California water resources in many ways, including through rising sea levels, reduced snowpack, and more frequent and severe droughts. Impacts and vulnerabilities vary by region resulting in the need for tailored actions to ensure the viability of regional watersheds, including the Kern Region. These actions focus on reducing the intensity of climate change through mitigation measures and adapting to climate change effects. This technical memorandum identifies the potential climate change vulnerabilities in the Kern Region as well as potential future actions to mitigate the vulnerabilities to climate change. The climate change vulnerability assessment presented in this section includes the checklist assessment in DWR s Climate Change Handbook for Regional Water Planning and is consistent with climate change requirements in the Proposition 84 IRWMP Guidelines (June 2014). 1.1 Climate Change Projections A climate change assessment is performed using the output of computer models that project future conditions from inputs on GHG emissions. These models are not predictive, but provide projections of potential future climate scenarios that can be used for planning purposes. Climate change has the potential to have significant impacts on the Kern IRWM Region. The U.S. Bureau of Reclamation (Reclamation), the State of California and others continue to study climate change and its potential impacts on water and other resources in the western states. The primary climate variables projected by global climate models (GCMs) that are important for water resources planning in California are changes in air temperature, changes in precipitation patterns, and sea level rise. The State of California 2009 Climate Change Impacts Assessment (California Climate Change Center 2009) provides the scientific basis for developing statewide climate change impact projections. The 2009 assessment provided future climate projections to

2 Page 2 support water resources decision making in California. A set of six GCMs were run for two GHG emissions scenarios, A2 and B1, selected from the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES). The IPCC report provides a family of common scenarios that cover a range of plausible trends in GHG emissions over the 21st century as a result of economic, technological, and population change (IPCC 2007). Scenario A2 assumes higher GHG emissions and high growth in population and represents a more competitive world that lacks cooperation in development (similar to business as usual), while B1 is a lower GHG emission scenario that represents social consensus for sustainable development. Each GCM was used to simulate a historical period from and a future projection period from 2000 to The period serves as a baseline or present condition for the models so that future conditions can be projected. Table 1 lists the six GCM models and their sponsoring organization, the combination of which were used to evaluate climate change impacts in the Kern Region. Table 1: Summary of Global Climate Models GCM Sponsoring Organization and Model Name NCAR-PCM1 (a) National Center for Atmospheric Research (NCAR) Parallel Climate Model (PCM) National Oceanic and Atmospheric GFDL-CM21 (a) Administration (NOAA) Geophysical Fluids Dynamics Laboratory (GFDL) model, version 2.1 NCAR-CCSM3 (a) NCAR Community Climate System Model (CCSM) Max Plank Institute ECHAM5/MPI-OM MPI-ECHAM5 Used by DWR for its climate change analysis for the 2011 Reliability Report, but the 2013 Draft Report Update uses Bay Delta Conservation Plan (BDCP) LLT CC5 input hydrology. MIROC 3.2 medium-resolution model from the Center for Climate MIROC32 System Research of the University of Tokyo and collaborators CNRM-CM3 (a) French Centre National de Recherches Météorologiques (CNRM) models Cal-Adapt website. Average of the following four GCMs: NCAR-PCM1, Four Model Average (a) GFDL-CM21, NCAR-CCSM3, and CNRM-CM3. Used in this analysis for Kern River Region Note: (a) Model used by Cal-Adapt. DWR used the MPI-ECHAM5 model with the A2 emissions scenario when preparing the 2011 State Water Project Delivery Reliability Report. MPI-ECHAM5 represents the median of the six GCMs listed in Table 1. However, the 2013 Draft Delivery Reliability Report (December 2013) uses the climate change input hydrology developed for the Bay Delta Conservation Plan (BDCP) for the Late Long Term planning horizon and the 5th climate change region (BDCP LLT

3 Page 3 CC5 input hydrology). This had the effect of lowering SWP long-term future reliability, from 60% to 58%. The California Energy Commission s Public Interest Energy Research Program (PIER) recently established the Cal-Adapt website ( whose purpose is to explore California s climate change research. In part, the website provides output from four climate models (NCAR-PCM1, GFDL-CM21, NCAR-CCSM3, and CNRM-CM3) and two GHG emission scenarios (A2 and B1) downscaled to any location in California. The four GCMs are a subset of the six GCMs identified in Table 1. Because the BDCP LLT CC5 GCM is not included in Cal- Adapt, an average of the four GCMs (also provided by Cal-Adapt) with the A2 emission scenario was used in this analysis for the Kern Region. 1.2 Kern Region Climate Change Projections Climate change is expected to have various impacts on the Kern Region including: (1) changing hydrology due to a shift from snow to rain precipitation, (2) higher wildfire risk due to warmer, drier conditions over the year, and associated impacts on water quality and flooding, (3) fluctuations in temperature resulting in longer and drier conditions over the year, and associated impacts on water quality and flooding, (4) longer and more severe multi-year droughts, (5) greater summer water demand from all categories of users and (6) impacts to habitats and species Temperature Cal-adapt projects that locally, overall air temperatures are expected to rise from 1 F to 2.3 F over the next few decades. The historical average annual temperature in the Kern region is 61.4 F; the A2 and B1 scenarios project increases of 3.5 F and 6.3 F by the end of the 21st century. Figure 1 shows the projected air temperature change for the four GCMs averaged from 2000 through 2100, compared with the historical baseline from The projected temperature increases begin to diverge at mid-century so that, by the end of the century, the temperature increases projected in the higher emissions scenario A2 are almost twice as high as those projected in the lower emissions scenario B1.

4 Page 4 Figure 1: Historical and Projected Annual Average Air Temperature for Kern County Source: Cal-adapt.org. Bakersfield Area In addition to overall temperature increases, the region is projected to encounter higher incidences of extreme temperatures. Figure 2 and Figure 3 show the projected increases in extreme temperature days in Kern County for the B1 and A2 emission scenarios. This chart displays a count of the number of days that the selected area on the map is projected to exceed the area s calculated extreme heat threshold of 101 degrees F for each year The historical annual average number of extreme heat days is four. Both scenarios project that number will increase to about 30 days by mid-century and either 40 or 70 days by the end of the century, depending on the emissions scenario.

5 Page 5 Figure 2: Number of Extreme Heat Days (Low Emission Scenario) Source: Cal-adapt.org. Bakersfield Area

6 Page 6 Figure 3: Number of Extreme Heat Days (High Emission Scenario) Precipitation Source: Cal-adapt.org. Bakersfield Area Precipitation in the Kern Region is essentially all due to rain, and significant shifts in the timing of precipitation are not expected to occur. On average the projections indicate little change in total annual precipitation in California. Furthermore, among several models, precipitation projections do not show a consistent trend during the next century. The Mediterranean seasonal precipitation pattern is expected to continue, with most precipitation falling during winter from North Pacific storms. One of the four climate models projects slightly wetter winters, and another projects slightly drier winters with a 10 to 20 percent decrease in total annual precipitation. However, even modest changes would have a significant impact because California ecosystems are conditioned to historical precipitation levels and water resources are nearly fully utilized. Figure 4 shows the decadal precipitation projections from 1960 through 2100 for the Bakersfield area in Kern County. There appears to be continued variable precipitation over the next century, with an overall consistent decrease. The drier conditions projected may result in a higher wildfire risk in the Region.

7 Page 7 Figure 4: Projected Annual Precipitation for the Bakersfield Area in Kern County Wildfire Source: Cal-adapt.org. Bakersfield Area Fire is an important ecosystem disturbance. It promotes vegetation and wildlife diversity, releases nutrients into the soil, and eliminates heavy accumulation of underbrush that can fuel catastrophic fires. The area projected to be burnt by wildfire toward the end of the century will increase substantially, especially in mountainous areas. As climate changes, it appears that summer dryness will begin earlier, last longer and become more intense. These changes may exacerbate fire occurrences, which have historically peaked in late summer and early fall. If temperatures rise into the medium warming range, the risk of large wildfires in California could increase by as much as 55 percent, which is almost twice the increase expected if temperatures stay in the lower warming range. Because wildfire risk is determined by a combination of factors including precipitation, winds, temperature, and landscape and vegetation conditions, future risks will not be uniform throughout the state. In years with wet winters, annual vegetation growth is plentiful. But accentuated dryness during summer would produce a hazardous fuel load that worsens the wildfire problem in some of Southern California wildlands. With expanding development into the urban/wildland interface, threats to human safety and property are even greater. The spread of invasive species that are more fire-prone, coupled with more frequent and prolonged periods of drought, all increase the risk of fires, and reduce the capacity of native species to recover.

8 Page 8 Wildfires are also bad news for the region in terms of air quality, human health, soil erosion and stress on watersheds. Figure 5 shows projected increases in potential area burned in the Bakersfield area of Kern County. These data are modeled solely on climate projections and do not take landscape and fuel sources into account. New wildfire risk projections are currently being produced that take more landscape information into account. Figure 5: Projected Increase in Potential Area Burned in the Bakersfield Area of Kern County Source: Cal-adapt.org. Bakersfield Area Fire is an important process in maintaining a diverse ecosystem in the Region. It is unclear at this time whether projected increased wildfire risk will be beneficial or harmful to long term ecosystem health and habitat maintenance, but will likely negatively impact water quality. Scenario: A coherent, internally consistent and plausible description of a possible future state of the world. It is not a forecast; rather, each scenario is one alternative image of how the future can unfold. A set of scenarios is often adopted to reflect, as well as possible, the range of uncertainty in projections. Other terms that have been used as synonyms for scenario are "characterization", "storyline" and "construction.

9 Page Resources in the Kern Region Vulnerable to Climate Change This section identifies the resources within the Kern Region and their potential vulnerability to climate change. Table 2 provides a general overview of the water-related resources that are considered important in the Kern Region and potentially sensitive to future climate change. Resources that are likely to be vulnerable to climate change are considered for further analysis in the preceding subsections. Table 2 also highlights those resources in the Region that are unlikely to be affected by climate change and therefore they do not warrant further analysis and consideration at this time. The summary table provides the main categories applicable to water planning in the Kern Region with a general overview of the qualitative assessment of each category with respect to anticipated climate change impacts. Table 4 in Section 1.4 below provides the complete assessment of the regional vulnerability to the potential climate change impacts using the Vulnerability Assessment Checklist, found in the Climate Change Handbook for Regional Water Planning (DWR, 2011). Table 2: Climate Change Vulnerability Assessment Overview Watershed Characteristics Water Demand General Overview of Vulnerabilities Urban and Agricultural Water Demand Changes of hydrology in the Region as a result of climate change could lead to changes in water demand, both in quantities and patterns. Increased irrigation (outdoor landscape or agricultural) is anticipated to occur with temperature rise, increased evaporation losses with warmer temperature and longer growing season.

10 Page 10 Watershed Characteristics Water Supply Water Quality Sea Level Rise Flooding General Overview of Vulnerabilities Imported Water State Water Project (SWP) and Central Valley Project (CVP) water is an important portion of the water resources available to the Region. Potential impacts on SWP and CVP water availability resulting from climate change directly affect the amount of imported water supply delivered to the Region. Groundwater Changes in local hydrology could affect natural recharge to the local groundwater aquifers and the quantity of groundwater that could be pumped sustainably over the long-term. Decreased inflow from runoff, increased evaporative losses, warmer and shorter winter seasons can alter natural recharge of groundwater. In addition, additional reductions in the imported water imposed by climate change would lead to more reliance on local groundwater, resulting in reductions in base flows, reduced groundwater outflows, increased depth to groundwater and increased land subsidence Imported Water Sea level rise could result in increases in chloride and bromide (a disinfection by product precursor), potentially requiring changes in drinking water treatment. Increased temperature could result in increase in algal blooms and taste and odor events. Regional Surface Water Increased temperature could result in lower dissolved oxygen in the Kern River and its tributaries. Decrease in annual precipitation could result in higher concentrations of contaminants in these surface waters during droughts. Increased wildfire risk and flashier storms could increase turbidity loads for water treatment. The Kern Region is not directly subject to sea level rise. However, potential effects of sea level rise would affect imported water supply conditions. As discussed above, the principal concern is the potential for sea water intrusion to increase Delta salinity. While sea level rise is not a direct regional concern, pursuant to the California Ocean Protection Council Resolution adopted March 11, 2011, it should be considered in the project selection/prioritization process. Local surface flows could change as a result of more frequent and intense storm events, leading to more areas susceptible to flooding, and increasing risk of direct flood damage in the Kern Region.

11 Page 11 Watershed Characteristics Ecosystem and Habitat Hydropower General Overview of Vulnerabilities Increased temperature and potential decreases in annual precipitation could put stress on sensitive ecosystems and alter habitats. Waterdependent recreation could also be affected by water quality impacts. In addition, the Kern Region may be subject to increased wildfire risk, which could alter habitat. Hydropower production in the Kern Region is very minimal, thus, climate change effects on hydropower are not considered to be significant or warrant further analysis at the time of this IRWMP update. Climate change processes are supported by extensive scientific research and are based on a vast number of peer-reviewed and published technical literature. Much of the available literature presents general information, but there is relatively little information that presents specific tools on how to apply impacts in the context of addressing climate change impacts on water resources. In addition, far less information is available on smaller geographic areas and the spatial resolution of the existing climate change models is still quite low. One additional challenge is that precipitation projections cannot be easily converted directly into surface runoff and groundwater recharge to connect with the local water resources planning activities. The following sections present the vulnerability of each sector identified in Table 2 with respect to climate change projections given the existing tools and available data. This is an initial attempt using projections specific to the Kern Region for the vulnerability assessment in support of the IRWMP. The outcome of this initial assessment is intended to help understand the potential impacts, to integrate climate change into long-term planning, and to improve understanding of the uncertainties associated with climate change effects. Consistent with the water resources planning horizon in the Kern Region through 2050, the vulnerability analysis considers projections for mid-21 st century (2050), consistent with DWR s modeling approach to climate change Water Demand Increasing air temperatures due to climate change will result in increased evaporation leading to drier soils, increased plant evapotranspiration (ET), and a longer growing season. All of these factors generally increase water demand however there are not sufficient data available to quantify the effect from increasing temperature resulting from climate change.

12 Page 12 The Cal-Adapt A2 emissions scenario projects an average temperature increase for the Kern Region of about 3.3 F by the mid-century (2050) and increase of about 6.3 F by the end of century (Figure 1). Characterizing the impacts of temperature rise on water demand is a difficult task and discussed on a qualitative basis. While water use varies considerably depending on other factors such as regional economy, population, and land use, a qualitative assessment of water demand increase can be noted based on the projected temperature increase from the Cal-Adapt emission scenarios. Kern County is characterized by its traditional industries, agriculture, oil and gas production, as well as increasing urbanization and population growth. Total water demand for the region is projected to increase only slightly. Water use to meet municipal water needs are projected to increase significantly - about 48 percent from approximately 189,162 acre-feet per year (AFY) in 2005 to 281,284 projected for However most of the use in the Kern Region is agricultural. Although historically the trend of agricultural water use has been decreasing, for purposes of this report future agricultural water demands are assumed to stay the same at 2,669,713 AFY. Total 2005 urban and agricultural demand for the Kern Region is estimated at around 2,857,755 AFY and projected 2030 total demand is estimated to be 2,938,818 AFY, a change of just under 3 percent. An important effect of changing weather conditions is likely to be on landscape and agricultural demand. Higher temperature generally increases ET rates; but some research studies also suggest higher CO2 levels and higher temperature increase rates of plant growth, and can shorten the time to plant maturity (Hanak and Lund, 2008). This would reduce the overall plant water uptake, partially compensating for potential reductions in agricultural water supply. Thus, the net effect on agricultural crops is still uncertain (Kiparsky and Gleick, 2005) and remains an important area of on-going research. Qualitatively, the ET projections with climate change suggest water demand for agriculture in the Region is anticipated to increase during months where ET is high and decrease in months where ET is low. As a result of increased ET, urban water demand is anticipated to increase as well because of greater outdoor water use for landscape irrigation and agriculture. Demand management is an important adaptation given decreased water supply as a result of climate change. Agriculture has a variety of water demand management options including fallowing fields of annual crops and changing the crop itself to one that may be less water intensive, yet economically viable. Additionally, in some cases, farmers may be able to switch their water source from surface water to groundwater. Demand management options for the urban landscape sector range from climate appropriate plants to improved irrigation methods. Water demand management strategies are discussed in Section 11.2 in the November 2011 Kern IRWM Plan.

13 Page Water Supply For long-term water supply planning, coping with variability is a challenge. With potential additional changes imposed by climate change, there will be a heightened need to evaluate and respond to increased water supply variability. Climate change is expected to affect Regional imported water supplies as follows: Total precipitation is expected to decrease in the Sierra Nevada sources reducing runoff to surface supplies. Snow pack projected to decrease from less storage in the mountains. Precipitation projected to shift toward more rain and less snow. Timing of runoff is expected to shift to earlier in the year, affecting reservoir storage especially in the spring and summer months. Sea-level rise may impact Delta water deliveries. Climate change is expected to affect Regional surface and groundwater supplies as follows: Total precipitation is not projected to change significantly however the trend is decreasing. Variability in annual precipitation is expected to continue, with vulnerability to droughts. More intense storms anticipated that may affect surface water runoff and storage and groundwater recharge. Oil and gas drilling in the county could be impacted by decreasing water availability, particularly in times of drought by limiting the amount of water available for cooling, fuel extraction, and power generation. The effects of climate change and water availability on the oil and gas sector include a combination of potential direct and indirect impacts. Water is required in many different stages of the oil and gas value chain, from exploration to processing to transport, and the volume of water used in these activities varies, with the largest volume used in the refining process. Among exploration and production processes, the largest volume of water is used as a supplemental source. Because the Kern Region relies heavily on imported supplies, any reduction or change in the timing or availability of those supplies could have negative impacts on the Region. Reductions in

14 Page 14 imported water supplies would lead to increased reliance on local groundwater, recycled water or other sources of supplies if demand was not reduced. Changes in local hydrology could affect surface storage of water and natural recharge to the local groundwater and the quantity of groundwater that could be pumped in a sustainable manner. The following sections describe potential climate change impacts to the region's water supplies Imported Supplies Imported water deliveries to the Kern Region are from the SWP and CVP via the California Aqueduct, and the CVP via the Friant-Kern Canal. Increasing development and environmental demands on water availability and quality for agricultural and M&I purposes, coupled with curtailments of imported SWP and CVP deliveries due to prolonged drought and regulatory restrictions, have intensified the competition for available water supplies in the Kern Region. It is estimated that due to drought and decreases in imported water supply, about 45,000 acres of farmland in the Region will be idled and an additional 100,000 acres will be under-irrigated. Climate change impacts are likely to exacerbate these challenges. In an effort to assess the impacts of these varying conditions on SWP supply reliability, DWR issues its State Water Project Delivery Reliability Report. DWR s long-term SWP delivery reliability analyses incorporate assumptions that are intended to account, among other impacts, for potential supply shortfalls related to global climate change. The long-term average delivery of contractual SWP Table A supply is projected to be 62 percent under current conditions and 58 percent under future conditions over the 20-year projection (DWR 2013). Within that longterm average, SWP Table A deliveries can range from 12 percent (single dry year) to 97 percent (single wet year) of contractual amounts under current conditions, and from 11 percent (single dry year) to 98 percent (single wet year) under future conditions. Contractual amounts are projected to be 31 percent during multiple-dry year periods (assuming a 4-year dry period), and from 81 to 85 percent during multiple wet periods (assuming a 4-year we period). Table 3 shows SWP supplies projected to be available to the Region in average/normal years and summarizes estimated SWP supply availability in a single dry year and over a multiple dry year period.

15 Page 15 Table 3: KCWA Wholesaler Supply Reliability (AF) Wholesaler (Supply Source) Average Water Year DWR (SWP) KCWA Table A Supply 579, , , ,263 % of Table A Amount(a) 58% 58% 58% 58% Single Dry Year DWR (SWP) KCWA Table A Supply 109, , , ,860 % of Table A Amount(a) 11% 11% 11% 11% Multiple Dry Year DWR (SWP) KCWA Table A Supply 309, , , ,606 % of Table A Amount(a) 31% 31% 31% 31% Note: (a) Percentages of Table A amount from DWR s 2013 SWP Delivery Reliability Report and assumes future conditions. Also assumes Table A contract amount of 998,730 AFY Groundwater The San Joaquin Valley groundwater basin covers the majority of the managed groundwater resources in the Kern Region. Other groundwater basins in the Kern Region include the Kern River Valley groundwater basin to the east; Walker Basin Creek Valley groundwater basin to the southeast; Cummings Valley and Tehachapi Valley West on the eastern side of the Region, Brite Valley to the southwest; and Cuddy Canyon Valley, Cuddy Ranch Area, Cuddy Valley; and Mil Potrero Area basins to the south. All of these groundwater basin boundaries are within the watershed boundary of the Kern Region (see Figure 2-7 in the November 2011 Kern IRWM Plan for basin locations). One of the longest-standing issues in the Kern Region is groundwater overdraft. Groundwater provides approximately 39 percent of local water needs; however it is estimated to be as much as 60 percent in dry years. Further, certain portions of the groundwater basin underlying the Kern Region have experienced overdraft conditions. According to DWR Bulletin 118, the basin

16 Page 16 generally underlying the Kern Region experiences a net loss to storage of approximately 325,000 AFY. The groundwater in the Kern Region may also be subject to decreasing reliability related to the extent and duration of longer drought periods that may occur due to climate change. There are limited data available to quantify the sustainable groundwater supplies and therefore to assess the resiliency of these supplies after drought events. A better understanding of groundwater supplies will be important to continued resiliency against climate change, as water supply management becomes a more important issue in the Region. While the basins have supply exceeding the future projected pumping levels, based on the basins' characteristics and their natural recharge processes, changes in local hydrology and natural recharge are anticipated to have a direct impact on available groundwater storage. Warmer winters would increase the amount of runoff available for groundwater recharge, but reductions in inflow from runoff and increased evaporative losses could reduce the amount of natural recharge. The extent to which climate change will change the natural recharge processes and the impact of that change are not exactly known and are difficult to quantify Water Quality Improving water quality is a Kern Region Plan objective that may be impacted by climate change. Studies of potential climate change impacts on water quality exist, but few trends in relationships between hydroclimate (hydrology and weather variables) have been identified. Key climate vulnerabilities potentially important to the Kern Region include increasing temperature and changes in precipitation patterns. Increased wildfire risk is another potential factor that could affect water quality in the Kern Region. Outside the Kern Region, sea level rise in the Sacramento-San Joaquin Delta is expected to impact water quality of imported SWP water. Surface waters in the Region are expected to be more directly vulnerable to water quality impacts of climate change, while water quality impacts to groundwater sources would be indirect Imported Water Quality SWP water currently meets or exceeds applicable standards (see Appendix D in the November 2011 Kern IRWM Plan for data). However, there is concern with some constituents that are approaching SWP acceptance criteria, particularly arsenic and selenium. SWP and CVP water is vulnerable to potential effects of climate change at the source in the Delta and in storage in Regional reservoirs. Sea-level rise will increase the intrusion of salinity into the Delta and its exported water. This will increase chloride and bromide (a disinfection byproduct [DBP] precursor that is also a component of sea water) concentrations in the SWP and CVP imported water. In addition, decreased freshwater flows into the Delta could increase the concentration of

17 Page 17 organic matter, which contribute to potentially higher DBP formation concentrations, in the SWP and CVP water. Imported water stored in Isabella Reservoir will also be vulnerable to climate change when considering reduced runoff volumes which could affect turbidity and increasing water temperatures, dissolved oxygen (DO) levels, and ph. Extreme storm events, although rare, may be more intense due to climate change and may present treatment challenges for source water because of increased turbidity. In the past, high turbidity events in reservoirs have required modification of the treatment processes (primarily additional chemical usage) for extended periods. In addition, an intense winter rainfall event after a wildfire in a watershed that burned the prior year can result in extremely high turbidities and fine organic matter in the lake water. The additional sludge production can overwhelm the treatment plants' solids handling equipment and require plants to be shut down or reduce their capacities for brief periods of time, or make capital investment to enlarge solids handling facilities. This combination of more intense rainfall events and increased wildfire risk is more likely under projected climate change conditions. The warmer temperatures could also lead to increased taste and odor events triggered by algal blooms; which are characterized by water quality changes during the spring and summer such as increases in DO and DO saturation, ph and fluorescence. Water treatment plants can be designed to address taste and odor events through pre-ozonation but use of higher ozone dosages to control taste and odor events must also consider the need to control bromate formation (from the oxidation of bromide), which could increase due to greater bromide levels in the imported SWP and CVP water affected by climate change Regional Surface Water Quality The primary regional surface water in the Kern Region is the Kern River. Local minor streams, many of which are ephemeral, provide additional local surface water. A very small percentage of minor stream runoff is collected and used as irrigation for agriculture; the majority of these irregularly-occurring flows serve to recharge local groundwater basins. The Kern River and its tributaries, while generally considered a high quality supply, are vulnerable to potential water quality impacts due to climate change as a result of increased temperature, more frequent heavy rainfall events, increased wildfire risk, and longer periods of low natural stream flow from decreased annual precipitation. Increased water temperature generally reduces dissolved oxygen and can promote algal blooms if nutrients are available in the source. The storm events can transport sediments and other pollutants along the river, while long periods of low flow can increase concentrations of pollutants from wastewater plant and non-point discharges. Increased wildfires may contribute to the turbidity events. Key water

18 Page 18 quality constituents of concern are nitrogen and chloride, in addition to reduced DO and increased algae growth, turbidity and sedimentation Groundwater Quality Groundwater quality throughout the region is typically suitable for most urban and agricultural uses with only localized impairments including high TDS (salts), sodium chloride, sulfate, nitrate, organic compounds, boron and arsenic. High TDS, arsenic and nitrates are the primary groundwater quality issues. Any water quality impacts to groundwater sources due to climate change are expected to be indirect, primarily due to decreased recharge from lower precipitation and increased use of groundwater to make up loss of imported water. Decreased recharge and increased groundwater pumping may allow concentrations of groundwater contaminants such as perchlorate and volatile organic compounds to increase, which may trigger additional treatment requirements and increase groundwater treatment costs Flooding Flooding is the most costly and destructive natural disaster; thus, a change in flood risk is a potential significant effect of climate change that could have great implications for the Kern Region. Some areas in the subregion are subject to periodic flooding, including the South Fork of the Kern River, Kelso Creek, and Erskine Creek. Under certain hydrologic conditions, some of these streams carry very large flows that can be damaging. The FEMA Flood Insurance Rate Map for the Kern Region designates multiple areas as High Risk, areas with a 1 percent or greater risk of flooding in any year and a 26 percent chance of flooding over the life of a 30-year mortgage. The area at greatest flood risk is the area surrounding the communities of Lamont, Weedpatch, and the city of Arvin. The area is also prone to wildfires, which impact water quality when rain washes fire debris into waterways. Other large flood area includes the Buena Vista lakebed as well as areas in the historic Tulare lakebed and nearby drainage areas. Areas along the Kern River and other local streams are also considered to have a high flood risk. These areas are depicted in Figure 2-8 in the November 2011 Kern IRWM Plan. Regional efforts to address flooding and to better manage such flow events have been initiated among various parties in the Kern Region, including the County of Kern, KCWA and the affected areas. For more information on flood management see Section 10.2 in the November 2011 Kern IRWM Plan. While the Cal-Adapt climate change model projects precipitation decrease of 10 percent by 2050 on the long-term basis, research data suggest that there is a risk of increased flooding in

19 Page 19 California (Kiparsky and Gleick 2005). Flooding depends not only on average precipitation but on the timing and intensity of precipitation. Climate change projections are not sensitive enough to assess short term extreme events such as flooding, but the general expectation is that more intense storms would occur. This could present larger areas susceptible to flooding and increase the risk of direct flood damage in the Region Ecological Health and Habitat Ecosystem health and habitat protection are important to the Kern Region. Increased temperature, changes in precipitation patterns, and increased wildfire risk projected for potential climate change scenarios are potential stressors to ecosystems and habitat in the Region. Environmental resources of the Kern Region include the Kern River, Sequoia National Forest, several wildlife refuges, and the unique flora and fauna of the Tejon Pass area and Transverse Ranges. The riparian forest along the South Fork Kern River in the vicinity of Onyx and Weldon is one of the highest quality and most extensive stands of that vegetation type in California. This section of the river has the largest populations of Southwestern willow flycatchers and yellow-billed cuckoos in California. Much of this forest is conserved in the USFS South Fork Wildlife Area, Audubon California s Kern River Preserve, and CDFG s Canebrake Ecological Reserve. For more detail on the Kern Region's ecological resources, see Section 2.4 in the November 2011 Kern IRWM Plan. All of these species and habitats have acclimated to the historical climate and water resources and may or may not to adapt to potential changes due to future climate change. Increased air temperature will increase water temperature in rivers, tributary streams, ponds, and lakes, with resulting decreases in DO. This combination may stress fish and biota that depend on higher DO levels and colder water which may impact their sustainability. The increased annual average air temperatures may also alter plant habitat by changing the length and timing of the growing season and/or allowing non-native species to outcompete native species and disrupt ecosystems that depend on the present habitats. Thus, measures to control non-native species may be needed to maintain habitats. Water available for plant habitat could be impacted by potential decreases in annual precipitation and increases in ET due to projected increases in temperature. Decreased precipitation could also directly affect formation of vernal ponds. Ackerly et al. (2012) summarizes existing research on the relationship between climate and biodiversity and how changes in climate historically have and will in the future impact habitat. In terrestrial systems, the impacts of rising temperature and changing precipitation patterns have the largest effect and that in estuarine and intertidal areas, sea-level rise results in the most important direct impact. These habitats may be affected directly by habitat loss through erosion,

20 Page 20 or indirectly via human responses such as coastal armoring (e.g., construction of sea walls) and other infrastructural changes. 1.4 Regional Vulnerability Assessment Table 4 provides an assessment of the regional vulnerability to the potential climate change impacts using the Vulnerability Assessment Checklist, found in the Climate Change Handbook for Regional Water Planning (DWR, 2011). This checklist provides a further evaluation of the effects on regional water demands and supplies, as well as water quality, flooding events, environmental and ecosystems, and hydropower systems within the Kern Region.

21 Page 21 Kennedy/Jenks Consultants Table 4: Vulnerability Assessment Checklist Resource Checklist Item Kern Regional Condition Water Demand Are there major industries that require cooling/process water in your planning region? Does water use vary by more than 50% seasonally in parts of your region? Are crops grown in your region climate-sensitive? Would shifts in daily heat patterns, such as how long heat lingers before night-time cooling, be prohibitive for some crops? Do groundwater supplies in your region lack resiliency after drought events? Kern County is characterized by its traditional industries, agriculture, oil and gas production, as well as increasing urbanization and population growth. Oil and gas drilling in the county could be impacted by decreasing water availability, particularly in times of drought by limiting the amount of water available for cooling, fuel extraction, and power generation. Additionally, process water is required in packing plants and other locations for processing crops harvested from the field, further contributing to the significance of the use. Yes. A significant amount of water in the Kern Region is used for agricultural purposes, the demand for which fluctuates greatly in the summer compared to the winter. Yes. The Kern Region is the third largest agricultural county in the state in economic value, and produces over 250 different crops, including over 30 types of fruits and nuts, over 40 types of vegetables, over 20 field crops, lumber, nursery stock, livestock, poultry and dairy products. Many of these are climate-sensitive and could be prohibitively affected by shifts in daily heat patterns. With only six (6) inches per year of average rainfall, groundwater is necessary to maintain a sufficient water supply in the semi-desert climate of the Region. It is estimated that on average groundwater accounts for 39 percent of total water supply to the Region; however, it is estimated to be as much as 60 percent during dry years. Agriculture is estimated to be the largest user of groundwater.

22 Page 22 Resource Checklist Item Kern Regional Condition Are water use curtailment measures effective in your region? Are some instream flow requirements in your region either currently insufficient to support aquatic life, or occasionally unmet? Water Supply Does a portion of the water supply in your region come from snowmelt? Stakeholders of this IRWMP have identified water use efficiency as an important component of water supply planning. One of the stated objectives of this IRWMP is to Pursue and implement cost effective water use efficiency programs. In addition to direct water use efficiency, stakeholders have expressed a desire to improve system operation, reduce system water loss, and decrease energy use related to water infrastructure. Another objective of this IRWMP is to Replace aging infrastructure to reduce system water losses, improve operational efficiencies, and reduce service interruptions. No. However, since 1994, the two large projects that import water into the Kern Region, the CVP and the SWP, have been incrementally impacted by environmental and regulatory requirements that have served to diminish the ability of the projects to reliably deliver water supplies. A large proportion of recent imported water cutbacks has stemmed from fishery issues in the Sacramento-San Joaquin Delta, where the pumping plants for the CVP and SWP are located, as well as San Joaquin River Settlement or Public Law where water previously supplied to the CVP Friant Division for M&I and agricultural irrigation is being diverted into the San Joaquin River for in-stream flows. Yes. The Kern River is fed by annual snowmelt from the Southern Sierra Nevada, including Mount Whitney.

23 Page 23 Resource Checklist Item Kern Regional Condition Does part of your region rely on water diverted from the Delta, imported from the Colorado River, or imported from other climate-sensitive systems outside your region? Does part of your region rely on coastal aquifers? Has salt intrusion been a problem in the past? Would your region have difficulty in storing carryover supply surpluses from year to year? Has your region faced a drought in the past during which it failed to meet local water demands? Yes. The Kern Region receives SWP and CVP water delivered through the Delta, which is affected by climate change. The Kern Region does not rely on coastal aquifers. While salt intrusion from coastal aquifers is not applicable, salt management is still an issue in the region with regard to increasing salinity in groundwater. Salt in imported water supplies such as the SWP and CVP is the major source of salt which circulates throughout the groundwater in Kern County. There is limited carryover available for SWP water in San Luis Reservoir. Carryover of Kern River water in Isabella Reservoir is limited by the Reservoir s flood control purpose and US Army Corps of Engineers Regulations. However, there are opportunities to expand the Region s groundwater storage capabilities. No. Water demands have been met through the use of groundwater which, during drought, can result in significant declines in groundwater levels. To the extent that surface water supplies are reduced in the future (as a result of climate change and/or regulatory constraints), recharge will be reduced, which will affect the availability of groundwater for meeting local water demands.

24 Page 24 Resource Checklist Item Kern Regional Condition Water Quality Does your region have invasive species management issues at your facilities, along conveyance structures, or in habitat areas? Are increased wildfires a threat in your region? If so, does your region include reservoirs with fire-susceptible vegetation nearby which could pose a water quality concern from increased erosion? Does part of your region rely on surface water bodies with current or recurrent water quality issues related to eutrophication, such as low dissolved oxygen or algal blooms? Are there other water quality constituents potentially exacerbated by climate change? Are seasonal low flows decreasing for some waterbodies in your region? If so, are the reduced low flows limiting the waterbodies assimilative capacity? Yes. Aquatic pests, including invasive plants have been fought on the Kern River for decades. Prevention and control of invasive species is an ongoing battle by many resource agencies such as the Kern River Preserve Audubon Society, and the Kern River Ranger District. Yes. Parts of the Kern Region are prone to wildfires, which impact water quality when rain washes fire debris into waterways. In July 2008, the Piute Fire burned a significant area in the region. It was soon followed by a summer thunderstorm, which washed fire debris into the South Fork and ultimately down the Kern River. Many water purveyors were forced to switch from Kern River water to alternate sources to avoid contamination of settling ponds and costly treatment of the water. Yes. The Kern River, the primary native surface supply in Region, is generally considered a high quality supply. However, Isabella Lake which serves as the source for the lower Kern River is listed on the 303(D) list for dissolved oxygen and ph. Climate change could exacerbate these water quality conditions from increased temperatures. Possibly. Annual Kern River flows and flows in local ephemeral streams could be decreasing through time.

25 Page 25 Resource Checklist Item Kern Regional Condition Are there beneficial uses designated for some water bodies in your region that cannot always be met due to water quality issues? Does part of your region currently observe water quality shifts during rain events that impact treatment facility operation? Sea Level Rise Has coastal erosion already been observed in your region? Are there coastal structures, such as levees or breakwaters, in your region? Is there significant coastal infrastructure, such as residences, recreation, water and wastewater treatment, tourism, and transportation) at less than six feet above mean sea level in your region? Are there climate-sensitive low-lying coastal habitats in your region? Are there areas in your region that currently flood during extreme high tides or storm surges? Is there land subsidence in the coastal areas of your region? Do tidal gauges along the coastal parts of your region show an increase over the past several decades? No. Water is intended for many beneficial uses including agricultural water supplies, groundwater recharge, water replenishment, recreation, wildlife habitat, rare and endangered species, and wetland ecosystems. Most of these are met within the Kern Region; however there are two TMDLs for Lake Isabella with regard to DO and ph. No. No. The Kern Region is located in the Southern San Joaquin Valley, and concerns regarding coastal regions are not applicable. No. No. No. No. No. No.

26 Page 26 Resource Checklist Item Kern Regional Condition Flooding Does critical infrastructure in your region lie within the 200-year floodplain? Does part of your region lie within the Sacramento-San Joaquin Drainage District? Does aging critical flood protection infrastructure exist in your region? Have flood control facilities (such as impoundment structures) been insufficient in the past? Are wildfires a concern in parts of your region? Yes. The FEMA Flood Insurance Rate Map for the Kern Region designates multiple areas as High Risk, areas with a 1 percent or greater risk of flooding in any year and a 26 percent chance of flooding over the life of a 30-year mortgage. Figure 2-8 (in the November 2011 Kern IRWM Plan) shows the areas that are within the 100- and 500-year floodplain. Flooding can result in the inundation of structures, causing water damage to structural elements and contents, as well as impact damage to structures, roads, bridges, culverts, and other features from high velocity flows and from debris carried by floodwaters. No. Yes. In general, many Kern County communities are older and the physical components of their water systems are aging and outdated. Aging infrastructure is a particular issue for rural communities and DACs. Yes. The primary flood control facility in the Region is Isabella Dam on the Kern River. The dam protects the urban Bakersfield area and about 350,000 acres of agricultural land and oilfields. Kern River had an unregulated flow until 1954 when the Isabella Dam and Reservoir were constructed by the Army Corps of Engineers. Unfortunately, due to seepage and earthquake concerns, the flood control capacity of the reservoir has recently been limited. Yes. Parts of the Kern Region are prone to wildfires, which impact water quality when rain washes fire debris into waterways.